Prostate seed implant (brachytherapy)
A one-time procedure in which tiny radioactive seeds are placed permanently inside the prostate through thin needles passed through the skin between the scrotum and the anus. The seeds give a high dose of radiation to the prostate over several months while largely sparing nearby organs.
Also called Brachytherapy, LDR brachytherapy, Low-dose-rate brachytherapy, Seed implant, Prostate seeds, Radioactive seed implant, Permanent seed implant, Interstitial radiation
- Where
- Hospital or outpatient surgery center
- Anesthesia
- General or spinal anesthesia
- Time in the room
- About 1 to 2 hours
- Hospital stay
- Same day for most
- Going home with
- Usually none; a catheter for a few days if you cannot pass urine
- Back to normal
- A few days for most activities; urinary symptoms can last several months
- Back to work
- Usually within a few days to 1 week
Overview
Brachytherapy means radiation from very close range. In a low-dose-rate (LDR) seed implant, many tiny metal seeds, often about 60 to 120, each about the size of a grain of rice, are placed throughout the prostate. Their radiation travels only a few millimeters, so the prostate receives a high dose while the bladder and rectum receive much less.
The seeds stay in for good. Their radiation fades steadily, and depending on the type of seed, most of the dose is given within about 1 to 6 months. After about a year very little radiation remains, and the seeds are simply inert metal.
It is a team procedure. A urologist and a radiation oncologist work together with a medical physicist, who designs the dose plan. In many centers the urologist handles the ultrasound and needle placement while the radiation oncologist plans the dose and places the seeds, but teams divide the work in different ways.
Seeds alone are used for low-risk and favorable intermediate-risk cancers. For higher-risk cancers, seeds may be combined with several weeks of external radiation and hormone therapy, an approach called a brachytherapy boost. Recovery from the procedure is quick, but urinary irritation can last months, and some side effects of radiation appear gradually over years.
The parts of your body involved
The prostate sits below the bladder and in front of the rectum, with the urethra running through its middle and the perineum below it. Seeds are spread through the prostate in a pattern designed to cover the whole gland, including the cancer, while keeping the dose to the urethra and the rectal wall within safe limits.
- Prostate
The walnut-sized gland that receives the seeds. Glands that are very large can be harder to implant well.
- Urethra
The tube carrying urine through the prostate. It receives some radiation, which is why urinary irritation is common for months.
- Rectum
The bowel just behind the prostate. Its wall is kept below a safe dose limit, but some irritation can occur.
- Bladder
Sits above the prostate. The seeds stay inside the prostate and below the bladder.
- Perineum
The skin between the scrotum and anus, where the needles enter.
Why it’s done
A seed implant treats the whole prostate with radiation in a single visit. It suits men whose cancer is confined to the prostate, whose prostate is not too large, and who do not have major urinary blockage.
- Cure in a single procedure
For low-risk and favorable intermediate-risk cancers, long-term cancer control in large studies is similar to surgery and external radiation.
- Quick recovery
There is no incision. Most men go home the same day and return to normal activities within days.
- Lower risk of leakage
Lasting urine leakage is less common than after surgery, especially in men who have not had a prior TURP.
- A boost for higher-risk cancer
Combined with external radiation and hormone therapy, seeds allow a higher total dose to the prostate. A large trial named ASCENDE-RT found better PSA control with a seed boost, with more urinary side effects.
Other options
- Active surveillance
Watching the cancer with PSA tests, MRI and biopsies. Preferred for most low-risk cancers.
- External beam radiation
Radiation from outside the body over about 1 to 9 weeks, often with gold markers and a rectal spacer gel placed beforehand.
- High-dose-rate (HDR) brachytherapy
Temporary thin tubes are placed in the prostate and a strong radioactive source passes through them for minutes, then everything is removed. No seeds stay behind.
- Robotic radical prostatectomy
Removing the whole prostate with keyhole surgery.
- Focal therapy
Treating only the part of the prostate with cancer using heat or cold, for carefully selected men.
Getting ready
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Weeks before
The day before
The morning of
In the operating room, step by step
Press play or pick a step. Each drawing shows what your surgeon is doing at that moment. Your team may do some steps differently.
1. Going to sleep and positioning
You are put to sleep or given a spinal anesthetic. You lie on your back with your legs raised in padded supports. A catheter is placed in your bladder so the urethra can be seen on ultrasound, and an X-ray machine (C-arm) is brought over your pelvis.
After the operation
Right afterward
- Recovery room
You wake with some soreness between the legs. An ice pack helps limit swelling.
- Passing urine
You need to pass urine before going home. If you cannot, a catheter is placed for a few days.
- Radiation safety instructions
You receive written rules for the first weeks and a card that explains you have seeds, in case you set off a radiation detector, for example at an airport.
- Medicines
You usually go home on a medicine to relax the prostate, an anti-inflammatory, and sometimes a short course of antibiotics.
At home
- Urinary symptoms
Burning, frequent urination, urgency, getting up at night, and a weaker stream are common. They often build over the first weeks, are worst in the first 1 to 3 months, and settle slowly over 6 to 12 months.
- Soreness and bruising
The perineum may be bruised and sore for a few days. Blood in the urine is common for a few days.
- Bowels
Some men have loose stools, more frequent bowel movements, or rectal irritation. Avoid constipation and straining.
- Radiation safety
The radiation outside your body is very low. For the first couple of months, many teams advise not holding children on your lap for long periods and avoiding long close contact with pregnant women. Normal contact with adults, including sharing a bed, is generally fine. Follow your own team's rules, which depend on the seed type.
- If a seed comes out
Rarely, a seed passes in the urine. Do not touch it with your fingers. Use a spoon or tweezers, place it in a small jar, and call your team.
- Sex
You can usually resume sex after 1 to 2 weeks. Many teams advise using a condom for the first several ejaculations in case a seed passes. Semen may be dark or bloody for a while, and ejaculation can be uncomfortable at first.
- Activity
Light activity is fine after a day or two. Avoid heavy lifting and bicycle riding for about a week.
- Work
Most men return to work within a few days to a week.
Recovery timeline
- Day 0Implant day
The procedure takes about 1 to 2 hours, and most men go home the same day.
- Days 1 to 7Soreness settles
Bruising and soreness between the legs ease. Urine may be pink.
- About 1 monthDose check
A CT scan confirms where the seeds are and what dose the prostate received.
- Months 1 to 3Urinary symptoms peak
Frequency, urgency and burning are often at their worst. Medicines and avoiding bladder irritants help.
- Months 6 to 12Symptoms settle
Urinary symptoms slowly return toward normal for most men.
- Every 3 to 6 monthsPSA checks
PSA falls slowly, often reaching its lowest point after 2 to 3 years or longer.
- 1 to 3 yearsPossible PSA bounce
Some men have a temporary PSA rise that later falls again on its own. It is common after seeds and is not, by itself, a sign of cancer.
- Long termLate effects
Erections may weaken gradually over years. Rectal bleeding from radiation irritation can appear months to a few years later and usually settles.
What it feels like
Most men are surprised at how quick the procedure is and how slow the urinary symptoms are to settle. Knowing the pattern ahead of time makes the middle months easier to accept.
Choosing seeds
Meeting two or three specialists can feel confusing, and the idea of radiation staying inside you can be unsettling.
What helpsAsk each specialist to explain their role and the plan. Ask how many implants the team does each year.
Waking up
A bruised ache between the legs, and the strange thought that the seeds are now inside you.
What helpsUse ice packs and acetaminophen. Most men feel ready to go home within a few hours.
The first time you pass urine
Burning and a weak stream are common, and many men feel nervous about whether they will be able to go at all.
What helpsRelax, give it time, and sit if that is easier. Take the prostate-relaxing medicine as prescribed.
The long middle months
Frequent trips to the bathroom, urgency, and getting up several times at night can wear you down. Some men feel they are not getting better.
What helpsCut back on caffeine, alcohol, fizzy and spicy drinks. Spread fluids through the day and drink less in the evening. Ask about medicines for urgency. This phase usually eases by 6 to 12 months.
Being close to family
Worry about exposing a partner, children or grandchildren to radiation.
What helpsFollow your team's specific rules. Normal hugs and sharing a home are generally safe. The precautions are short-term.
Intimacy
Ejaculation may burn at first, semen may look dark, and some men worry about a seed coming out.
What helpsUse a condom for the first ejaculations if your team advises it. Over time, if erections weaken, effective treatments are available.
Watching the PSA
Because PSA falls slowly, and can bounce, every result can feel tense.
What helpsAsk your team what pattern to expect and what change would actually concern them.
How well it works
Success means a PSA that falls steadily to a low level and stays there, with urinary symptoms settling over the first year.
- Post-implant CT
A CT scan, often about a month after the implant, checks seed placement and the dose the prostate received.
- A slow PSA decline
PSA drops gradually, often for 2 to 3 years or more. Unlike after surgery, it may not become undetectable.
- PSA bounce
A temporary rise in the first few years is common and often settles without treatment. Your team watches it with repeat tests.
- When PSA signals a problem
After radiation, cancer return is usually defined as a PSA rise of 2.0 ng/mL above the lowest value reached. Further tests then look for where the cancer is.
Risks
Every operation has risks. These are the ones people ask about most, with honest odds where good numbers exist. Your surgeon’s own results matter more than averages.
Common
Burning, frequency, urgency, night-time urination and a weaker stream for months.
Bruising between the legs, and blood in the urine or semen for a short time.
Looser stools, urgency or rectal discomfort, usually mild and temporary.
Semen volume usually drops over time.
Erections may weaken gradually over the years after treatment. Pills and other treatments help many men.
Less common
Swelling can block urine in the first weeks, needing a catheter for a few days or longer. It is more likely with a large prostate or significant urinary symptoms before treatment.
Radiation can irritate the rectal lining (radiation proctitis), causing bleeding months to years later. It is usually mild and often settles.
Scar tissue can narrow the urethra years later and weaken the stream. It can be treated.
Lasting leakage is uncommon, but more likely if you have had a TURP or later need one.
A seed can occasionally travel through a vein to the lungs. This is generally harmless.
Rare
A sore or an abnormal channel between the rectum and urinary tract is rare and may need surgery. Avoid rectal biopsies after seeds unless your radiation team agrees.
A new cancer of the bladder or rectum caused by radiation, many years later, is very rare.
Call your care team or go to the emergency room if
- You cannot pass urine at all, or only dribbles, with a full, painful lower belly. Go to the emergency room if you cannot reach your team.
- Fever of 101°F (38.3°C) or higher, or shaking chills.
- Heavy bleeding or clots in the urine.
- Heavy bleeding from the rectum.
- Gas, stool or bubbles coming out in the urine.
- Severe or worsening pain between the legs or in the lower belly.
Questions to ask your surgeon
- Am I a good candidate for seeds, given my prostate size and urinary symptoms?
- Will I have seeds alone, or seeds with external radiation and hormone therapy?
- Who does which part of the procedure?
- Which type of seed will you use, and how long are the radiation precautions?
- How many implants does your team do each year?
- Will you use a rectal spacer?
- What urinary symptoms should I expect, and for how long?
- How will you follow my PSA, and what is a PSA bounce?
- What are my chances of erection problems over time?
Words you may hear
- Brachytherapy
- Radiation given from sources placed inside or very close to the area being treated.
- LDR (low-dose-rate)
- Seeds that give off radiation slowly over months and stay in place permanently.
- HDR (high-dose-rate)
- A temporary, strong radiation source passed through tubes for minutes, then removed.
- Radiation oncologist
- A doctor who specializes in treating cancer with radiation.
- Medical physicist
- A specialist who plans and checks radiation doses.
- Template
- A grid with rows of holes placed against the perineum to guide needles.
- Dosimetry
- Measuring and calculating the radiation dose the prostate and nearby organs receive.
- PSA nadir
- The lowest PSA value reached after treatment.
- PSA bounce
- A temporary rise in PSA after radiation that falls again without treatment.
- Radiation proctitis
- Irritation of the rectal lining from radiation, which can cause bleeding.
- Boost
- Extra radiation to the prostate, given with seeds, in addition to external radiation.
Common questions
Am I radioactive?
The seeds give off low-energy radiation that mostly stays inside the prostate. Very little reaches the outside of your body. Simple short-term precautions around young children and pregnant women are usually advised.
Can the seeds be removed later?
No. They are permanent, but after about a year their radiation is nearly gone and they are harmless.
Will I set off airport detectors?
Possibly, in the first months. Carry the card your team gives you.
Can I have an MRI?
The seeds do not prevent an MRI. Tell the MRI staff you have prostate seeds.
Can I have surgery later if cancer comes back?
Surgery after radiation is possible but harder and has more side effects. Other options include freezing, HIFU, or hormone therapy.
Is this the same as external radiation?
Both use radiation. Seeds treat from inside in one procedure; external radiation aims beams from outside over several sessions. Sometimes both are combined.
Sources this page draws on
- American Urological Association and American Society for Radiation Oncology, Clinically Localized Prostate Cancer: AUA/ASTRO Guideline (2022)
- American Brachytherapy Society, Consensus guidelines for transrectal ultrasound-guided permanent prostate brachytherapy (2012)
- International Journal of Radiation Oncology, Biology, Physics, ASCENDE-RT trial: dose escalation with a low-dose-rate brachytherapy boost versus external beam boost (2017)
- European Association of Urology, EAU-EANM-ESTRO-ESUR-ISUP-SIOG Guidelines on Prostate Cancer
- American Cancer Society, Radiation Therapy for Prostate Cancer
Written November 2026. This page explains what usually happens. It is not medical advice and does not replace a conversation with your own surgeon, whose plan for you comes first.